When each pickup is soloed, they sound ok, but when both are full up, the sound is very anemic.... The output is greatly reduced, and the tone sucks.

I wired it as my Mexican pickups had been wired. Is there some "special way" that these pickups should be wired? It seems to me that they are wired out of phase... does that sound right? However, I wired both the white wires to the volume pots, and the black wires to ground. I guess I could try switching the leads to one of the pickups and see if that makes a difference.

systematic checking of the connections that you made is the only way
out of phase sounds about right but why this should occur?
swapping wires on one of the pups is the only way
pup hots to pins 2
to jack outlets pins 1
ground pins 3 (bent tab to pot casing)
loop jack outlets to pin 2 on tone pot and then to jack?
tone cap from pin 3 to ground
tone cap pin 1 not used

After double, no, triple checking all my connections I tried switching the wires of the bridge pup. I grounded the white wire, and attatched the black wire to the volume pot. After doing this, it works perfectly. Why? I don't know... Were the leads to one of the pups switched at the factory? That's the only thing I can think of. But since these came out of a new bass, was the wiring switched in that, also? I don't know. At least it works now, and it will really confuse anyone that opens up the control cavity of my bass .

perhaps you have actually touched on the real reason
the original wiring to make use of any humbucking was wired mirror wise.
i dont know all the theory but that is the basic idea isnt it to buck hum
wire a pair contra wound and contra polarity
it may follow the wiring is contra as well
best to put a little label inside saying
beware these pickups bite! dont dare cross them
i bought s-d replacements for my ric and it was the same
i wired as per the diagram but had to 'reverse' one to avoid the phase cancellation
alls well that comes out of a bass amp?